“He had an injury,” Caldwell said, declining to provide specifics. “We’ll keep him out for a few days and see how he does.

“It’s day-to-day, so we’ll see how it goes,” Caldwell added later. “It’s nothing serious. He’ll be back, just maybe a day or two.”

Caldwell would not say whether the Lions will play Ebron in Saturday’s preseason opener against the Cleveland Browns. The coach was similarly noncommittal about whether the Lions will play Johnson, who had offseason surgery for knee and finger injuries that caused him to miss two games and numerous practices in 2013.

“With everybody, we look at every situation a little differently,” Caldwell said, “and we try and make certain that we do the prudent thing.”

The Lions have already taken measures to mitigate preseason wear and tear, first and foremost by instructing players to stay off the ground in practices and also by giving some veterans the occasional day off.

“At some point in time you have to be prudent, particularly with guys who have played in this league for a long time,” Caldwell said Tuesday. “We just think we need to periodically give them a little time off, particularly those guys that are getting in that 30-year-old range. Even though chronologically it’s not very old for the most part, but in this game you have to really keep an eye on them and take care of them where you can. From time to time we will do that for a number of guys. You’ll see the number of reduced reps that a number of guys that have been around awhile have had thus far.”

Lions center Dominic Raiola, one of the veterans to whom Caldwell has given a day off, has no interest in sitting out Saturday’s game.

“Of course I want to play – I want to be a part of this offense,” Raiola said with a hearty laugh.

Not only does Raiola want to play, he said he needs to do so, even with 13 NFL seasons already under his belt.

“I’ve always been one to callus my body and get ready to play,” Raiola said. “This is part of what it takes to play 16 games, and it’s been working to this point, so I don’t know why I’m going to change now.”

Raiola has not missed a game since 2008, however, while Johnson is coming off surgery and Ebron is currently injured.

If Johnson and Ebron have to sit on Saturday, at least fans will still have the expected entertainment value of Cleveland rookie quarterback and Internet sensation Johnny Manziel.